Tray unit for display stand



Dec. 13, 1960 T. F. ERICKSON TRAY UNIT FOR DISPLAY STAND 3 Sheets-Sheet 1 Filed Feb. 28, 1958 INVENTOR. THEODORE f EP/C/FSO/Y pfz gi V/W Dec. 13, 1960 T. F. ERICKSON 2,964,154

TRAY UNIT FOR DISPLAYSTAND Filed Feb. 28, 1958 s Sheets-Sheet .2

INVENTOR. 74500014 15 f f/P/f/(fiO/V Dec. 13, 1960 T. F. ERICKSON TRAY UNIT FOR DISPLAY'STAND 3 Sheets-Sheet 3 Filed Feb. 28, 1958 til!!! INVENTOR. THEODORE F f/P/c/(so/v BY Mv/W TRAY UNIT FOR DISPLAY STAND Theodore F. Erickson, Des Moines, Iowa, assignor to C. E. Erickson (30., Inc., Des Moines, Iowa, a corporation of Iowa Filed Feb. 28, 1958, Ser. No. 718,222

3 Claims. (Cl. 19335) This invention relates generally to display and delivery stands for use in self-service stores and in particular to such a stand wherein the articles are displayed on vertically arranged trays supported in inclined positions so as to deliver articles by gravity successively to the front of the stand.

Display and delivery stands for the self-service of articles are well known, especially for what may be termed hard goods such as can or carton goods. This type of goods is generally relatively heavy and has a firm or rigid supporting surface so as to be capable of travel by the action of gravity on tracks or rollers to a position at the front of the stand and without damage resulting from coming to a stop at such fi'ont position. However, in the handling of what might be termed soft goods, such as cellophane wrapped bakery goods, these prior art structures are not entirely satisfactory because of the drag or frictional resistance of the wrapping on the tracks or rollers.

Thus cellophane wrappings on bread, cakes and pastries are loose and these soft goods inherently have no firm surface. As a result, their bottom surfaces are not only yielding but the loose cellophane tends to drag and bunch up on the tracks or at the rollers. These problems can be overcome to a large extent by increasing the action of gravity on the soft goods, but this soltuion creates the further problem of possible damage to the goods, particularly the flattening of soft cakes, resulting from their sudden stop in a position at the front of the stand.

It is an object of this invention, therefore, to provide a display and delivery stand capable of successively feeding by gravity, both hard and soft goods, to a display position at the front of the stand without damage to the goods or articles.

A further object of this invention is to provide an inclined tray or rack unit for a display and delivery stand, the inclination of which is adjustable and wherein soft goods are carried in part on spaced rollers and in part on flat supporting surfaces located between the rollers, with the projection of the rollers above the flat supporting surfaces being such as to eliminate excessive drag of the goods on the supporting surfaces and bunching of the wrapping at the rollers, whereby to permit a proper feeding of the goods by gravity.

Another object of this invention is to provide a tray unit for a delivery and display stand having article supporting units which are releasably interlocked with a tray unit to provide for their removal for cleaning and inspection purposes.

A still further object of this invention is to provide a tray unit for a display and delivery stand wherein a front bail on the tray unit serves as a combination guard rail, interlocking member and lift member for moving the tray unit between locked display and loading positions therefor.

Another object of this invention is to provide an improved method for forming a roller article supporting unit for the tray unit of a display and delivery stand.

States Paton 2,964,154 Patented Dec. 13, 1960 A further object of this invention is to provide a tray unit for a display and delivery stand adapted to be loaded from the front of the stand, compact and light weight in construction, movably supported on adjustable inclined tracks, and readily manipulated for movement between loading and display positions by merely raising its front end.

Further objects, features and advantages of this invention will become apparent from the following description when taken in connection with the accompanying drawing in which:

Fig. 1 is a vertically foreshortened front perspective view of a delivery and display stand showing the tray units of this invention in their display positions;

Fig. 2 is an exploded detail perspectvie view, with cer-- tain parts broken away and other parts shown in section, showing the assembly of a tray unit guiding track with a looking or stop member for a tray unit;

Fig. 3 is a perspective view of a tray unit, with parts broken away to more clearly show its construction;

Fig. 4 is an enlarged foreshortened exploded detail perspective view showing the assembly of a track for a tray unit, with upright supports of the display stand Fig. 5 is a detail sectional view as seen along the line 55 in Fig. 4;

Fig. 6 is a foreshortened perspective view of an article separating member for partitioning a tray unit;

Fig. 7 is an enlarged detail perspective view of a por-v tion of a tray unit; 1

Fig. 8 is an enlarged exploded detail perspective view showing the means for releasably connecting an article supporting unit with the main frame of a tray unit;

Fig. 9 is an enlarged transverse sectional view of an article supporting unit showing parts thereof in position for final assembly together;

Fig. 10 is an enlarged transverse sectional view of an article supporting unit, illustrated similarly to Fig. 9, and as seen along the line 1(l10 in Fig. 7, and showing the parts thereof in final assembly;

Fig. 11 is an enlarged foreshortened side elevational view of an article supporting unit; a

Fig. 12 is an enlarged exploded detail perspective view of a front corner of a tray unit; and

Fig. 13 is an enlarged detail side elevational view of a front corner of a tray unit.

With reference to the drawings there is shown in Fig.. 1 a display and delivery stand having a pair of transversely opposed side sections 15 each of which includes front and rear supports 16 and 17, respectively. The side sections 15 are connected together by a lower front cross member 18 and rear cross members 19 and 21, so that the front of the stand is open between the side sections. Arranged in a vertically spaced relation between the side sections 15 are a plurality of tray units 22, only two of which are illustrated. Each traiy unit 22 is inclined downwardly and forwardly in a supported position on a pair of. tracks or guides 23 that are adjustably carried on corresponding upright supports 16 and 17. Since the tray units 22 in their assembly with associated tracks 23 are similar in construction and operation only one of such units 22 will be described in detail, with like numbers being used to designate like parts.

A tray unit 22 (Figs. 1 and 3) includes a main frame 25 having a pair of side sections 24 and a rear section 26 formed from a single piece of sheet metal. These sections are of a right angle shape in transverse cross.

section so as to have upright portions 27 and horizontal inwardly extended portions 28. The front section 2a of the main frame 25 (Figs. 3, l2 and 13) is of a substantially inverted U-shape in cross section and has a front leg 30, a rear leg 31 and a curved connecting base por- 3 5 tion 32, with the legs and 31 terminating in inwardly extended horizontal portions 33 and 34, respectively. Each end of the base portion 32 is notched or recessed as indicated at 36 to permit limited access between the leg members 30 and 31 for a purpose to later appear.

As shown in Figs. l2 and 13 a hook or ear 37 projects forwardly from the front end 38 of the upright portion 27 of a side section 24. The inner leg 31 of the front section 29, at a position substantially below the inner end of a recess 36 formed in the base portion 32, is formed with an upright slot 39. In assembly the side sections 24 and the front section 29 are relatively tipped to provide for the insertion of the hooks 37 within and through their corresponding slots 39 to a distance limited by the engagement of the front ends of the upright and horizontal portions of a side section 24 with the inner wall or leg 31 of the front section 29. With the side sections 24 thus interlocked with the front section 29, the front end of each horizontal portion 28 of a side section rests on top of the horizontal portion 34 of the inner leg 31 of the front section 29.

This interlocked engagement is maintained by means including a bail or lift member 40 (Figs. 3, 12 and 13), of a rod construction and of an inverted U-shape, having a base 41 and depending legs 42. The bail 40 is of a length to provide for the reception of the legs 42 between the legs 30 and 31 of the front section 29 at a position adjacent the inner ends of the recesses 36. As shown best in Fig. 12 each leg 42 terminates in an inwardly extended locking pin 43. On spreading the legs 42 apart for reception in the recesses 36, the pins 43 are inserted within corresponding openings 44 formed in the locking hooks or cars 37. It is seen, therefore, that the hooks 37 are in interlocking engagement with the front section 29 at the slots 39, and are maintained against any accidental movement out of the slots by the locking action of the pins 43 of the bail 46.

The main frame 25 (Fig. 3) is thus of a substantially rectangular shape, with the one piece member, comprising the side sections 24 and the rear section 26 thereof, releasably held in interlocked engagement with the front section 29, and with the upright portions 27 of the front and rear sections, and the inner leg 31 of the front section 29 forming a continuous peripheral upright wall. Likewise the horizontal portions 28 of the front and rear sections, and the horizontal extension 34 on the inner leg 31 of the front section 29, form a substantially continuous peripheral horizontal ledge.

Extended longitudinally of a tray unit 22 are a plurality of article supporting units 46 (Fig. 3), which are arranged in a spaced relation transversely of the tray unit 22. Each unit 46 includes a plurality of longitudinally spaced rollers 47 mounted in corresponding supporting or frame member 48. Since each article supporting unit 46 is similar in construction and operation only one of them will be described in detail, with like numbers designating like parts.

The frame member 48 of an article supporting unit 46 is of an inverted U-shape in transverse section (Figs. 7 and 8) having depending legs 49 and 50 and a flat connecting base 51, and of a length to extend between the upright portion 27 of the rear section 26, and the inner wall 31 of the front section 29. Each end of the base 51 terminates in a depending tab 52, positioned in a spaced relation between the legs 49 and 50, and having a substantially centrally located hole 53 therein of a rectangular shape.

Spaced longitudinally of the base 51 are a plurality of rectangularly shaped openings 54 corresponding to the rollers 47. As shown in Figs. 1 and 3 the outer rectangular openings in a unit 46, indicated as 54a and 54b, are spaced unequal distances from the ends of the frame member 48 for a purpose to be described hereinafter. A roller 47 is received between the legs 49 and 50 of a frame member 48, and is of a diameter greater than the width of a corresponding rectangular opening 54, with only a portion of'a roller 47 projecting upwardly from the base 51. Each roller 47 is provided with a shaft 56 carried in punched out openings 57 formed in the legs 49 and 5d of a frame member 48. The lug or bent portions 58 resulting from the forming of the holes 57, overlie the holes 57 so as to maintain the shafts 56 against axial movement out of supported positions on the legs 49 and 50. As illustrated, the rollers 47 are preferably of a plastic molded construction having a glass-like surface.

In the assembly of a frame member 48 with its roller and shaft assemblies 47 and 56, the frame member is initially formed with the rectangular openings 54, the punched out openings 57, the square openings 53 and the depending tabs 52, after which the tabs 52 are bent in a normal relation with the base 51 and the legs 49 and 50 are bent to form an obtuse angle with the base 51 as best shown in Fig. 9. Then, with the frame member 48 supported with the legs 49 and 50 extended upwardly, roller 47 and shaft 56 assemblies, corresponding to the openings 54, are placed within the openings 54. By virtue of the diameter of a roller 47 being greater than the transverse dimension of a rectangular opening 54, the rollers 47 are supported on the base 51 against the sides of a corresponding opening 54. The openings 57 in the legs 49 and 50 are arranged so that with the rollers 47 thus supported on the base 51 the roller shafts 56 are in substantial alignment with the openings 57. The legs 49 and 50 are then moved inwardly toward each other to positions substantially normal to the connecting base 51. This inward movement of the legs 49 and 50 provides for the reception of the ends of a roller shaft 56 within the openings 57 and adjacent to the overlying and maintaining bent portions 58.

As a result, the rollers 47 are quickly and economically assembled with the frame member 48 and their shafts 56 are positively retained against movement out of supported positions on the legs 49 and 50 by the bent portions or projections 58.

Each article supporting unit 46 is releasably secured in position to the tray main frame 25 by means including a pair of spaced hooks 61 for receiving therebetween a corresponding tab '52 (Fig. 8). The pairs of hooks 61 are integrally formed, by being punched out, in the inner leg or wall 31 of the front section 29 and in the upright portion 27 of the rear section 26. It is to be understood that the front wall 31 and the rear section 26 each carries a plurality of pairs of hooks 61 correspond ing in number to article supporting units 46 in a tray unit 22. Also, although pairs of hooks 61 are not illustrated for the rear section 26, it is to be understood that the pairs of hooks therein are similar in all respects to the pair of hooks '61 illustrated for the front section 29 in Fig. 8.

As shown in Fig. 8 the hook members 611 are extended longitudinally of the upright wall portion 31 and arranged so as to be open to each other. Intermediate a pair of hook members 61 is an inwardly extended depression 62 formed in the upright wall portion 31 and of a shape to fit within a. corresponding opening 53 of a tab 52.

Thus, in the assembly of an article supporting unit 46 with a tray main frame 25 a tab 52 is snugly received in interlocking engagement between a pair of corresponding hooks 61 to a position defined by the resting engagement of the legs 49 and 5th on the horizontal portion 34 of the front section 29, and where such assembly is at the rear end of a tray unit 22, with the horizontal portion 27 of the rear section 26. In this assembly position, a depres sion 62 is frictionally received within a corresponding tab opening 52 so as to releasably lock the frame member 48 of an article supporting unit 46 with a main frame 25 of a tray unit 22. As a result, although an article supporting unit 46 is locked against any accidental movement out of its assembly relation with a main frame 25, it can be readily removed for cleaning and inspection purposes by merely overcoming the frictional locking action of the depression 62 with a tab 52. It is to be noted further, by virtue of the flat abutting engagement of a tab 52 with a corresponding upright wall portion 31 on the front section 29, and upright portion 27 on the rear section 26, that rigidity is imparted to the main frame 25.

The guides or tracks 23 for the tray units 22 are similar in construction and operation so that only one of them will be referred to in detail. As shown in Figs. 2 and 4, a track 23 is of a generally U-shape having an upright base member 71, an inwardly curved or turned in upper leg 72, and a flat horizontally extended lower leg 73. For supporting a track 23 of a front support 16, the base member 71 thereof is integrally formed at a position spaced rearwardly from the front end of a track 23, with a punched out downwardly extended hook portion 76 arranged normal to the plane of the base 71. A front support 16 is of a channel shape, facing rearwardly and has its inner leg 77 formed with a plurality of vertically spaced openings 78 for selective reception of a hook 76.

An upright rear support 17 is also of a channel shape facing rearwardly and has its inner leg 79 formed with vertically spaced punched out loops 81 for selectively receiving a rearwardly extended tongue member 82 formed in the base 71 at the rear end of each track 23. The hook 76 is loosely received within a selected opening 78 and likewise a tongue 82 is loosely received within a selected loop 8 1. The loops 81 are spaced closer together than the openings 78 so that a downward and a desired forward inclination of a track 23 is readily accomplished by adjustment only of its rear end into a selected loop 81, while leaving the hook 76 at its forward end in the same opening 78. This adjustment is dependent upon the type of goods or articles to be displayed. In the present invention it has been found that an inclination of 17 is desirable for cellophane wrapped bread and an inclination of about 12 for cellophane wrapped cakes and the like.

In the assembly of a tray unit 22 the rear section 26 and side sections 24 are interlocked with the front section 29 by connection of the locking keys or hooks 37 on the side sections at the slots 39 of the front section 29, as was previously described in connection with Fig. 12. The bail 40 then has its pins 43 received within the openings 44 of the locking hoops to maintain such interlocked connection.

The article supporting units 46 are then interlocked at their tab portions 52 with their corresponding pairs of hooks 61 on the front and rear sections 29 and 26, respectively, by merely positioning a unit 46 between the front and rear sections above such hooks, and then pressing a tab portion 52 snugly between its corresponding pair of hooks. In this assembly the units 46 are arranged so that the outer openings in the frame member 48, indicated as 54a and 54b, and which openings are spaced inwardly unequal distances from the ends of a frame member 48, are alternately located at opposite ends of the tray unit 22. As a result the rollers 47 are arranged in a staggered relation over substantially the full area of a tray unit 22 as best appears in Figs 1 and 3. A tray unit 22 is then assembled with its associated pairs of tracks 23 by supporting the horizontal portions 28 of the side sections 24 on the horizontal legs 73 of the tracks 23, and guiding the upper edges of the upright portions 27 of the side sections 24, within the bent legs 72 of the tracks 23. The angle of inclination of the tracks 23 is dependent upon the type of goods to be displayed.

For the purpose of maintaining a tray unit 22 in in an extended loading position, or in a retracted display position, the horizontal portions 28 of the side sections 24 (Fig. 3) are each formed with a pair of longi tudinally spaced rectangular openings 83 and 84, with the openings 83 located near the front end of the tray, and with the openings 84 located near the rear end of the tray. These openings are of a size to snugly receive upright stop lugs 86 formed near opposite ends of a cross member 87 (Figs. 2. and 4) adjustably connected between a corresponding pair of tracks 23 adjacent their forward ends. A cross member 87 is of a fiat form with reinforcing ribs 88 and of a length to extend between the vertical base portions 71 of the tracks 23. Each end of a cross member 87 is formed with a depending forwardly facing hook 89 of an irregular shape adapted to be received within an enlongated opening 91, a plurality of which are formed in a spaced relation longitudinally of a track 23 at the junction of the horizontal track portion 73 with its base 71. The cross sectional dimensions of the shank 92 of a hook 89 are only slightly less than the corresponding dimensions of an elongated opening 91 so that upon reception of a shank 92 within an opening 91 a cross member 87 is held in a supported position on the track horizontal portions 73 against movement longitudinally of the track.

The stop lugs 86 are positioned Within the front openings 83 of a tray unit 22 to define a display position for the tray unit, and are receivable Within the rear openings 84 to define and hold a tray unit in a loading position. It is, of course, desirable for a proper display of goods on the tray units along with facilitating removal of the goods from the tray units, that the tray units be progressively extended forwardly of the stand from top to bottom of the stand. Since the track openings 91 are in opposed relation transversely of the stand, and a cross member 87 is adjustable longitudinally of the tracks 23, such a progressive arrangement is readily accomplished in the present invention. In other words the forward extension of a tray unit 22 from thefront of the stand merely requires a desired shifting of a cross member 87, to change the location of the stop lugs 86 longitudinally of the tracks 23. It will also be noted that the cross members 87 function as brace members between the side sections 15 of the display stand to impart greater rigidity to the stand.

For manipulating a tray unit 22 between its loading and display positions assume that a tray unit 22 is in a display position with the stops 86 within the front openings 83 and that the tray unit is to be moved to its loading position. The bail 40 at the front of the tray unit 22 is manually grasped and the front end of the tray raised an amount suflicient to remove the stop lugs 86 from within the openings 83, this upward movement of the tray being permitted by virtue of the fact that the base 71 of the tracks 73 is of a greater width than the height of the upright portions 27 of the side sections 24. With the tray unit thus held at the bail 40, it is moved forwardly until the rear openings 84 are at a position to receive the stop lugs 86. The same procedure is followed when the tray unit is to be moved from a loading to a display position.

Depending upon the articles to be displayed in tray unit 22, it is desirable that like articles, arranged in rows longitudinally of a tray unit 22, be separated from each other transversely of a tray unit. For this purpose the tray unit is provided with a plurality of separator or divider members 93 (Figs. 3 and 6), only one of which is illustrated in Fig. 3. A separator member is of a rod form of a reduced section at one end 94, and having a rectangular head portion 96 with a connecting neck 97 at its other end. For receiving the end portion 94 the upright portion 27 of the rear end section 26 is formed with a series of longitudinally spaced holes 98.

In alignment with the holes 98 in a direction longitudinally of a tray unit 22, the front leg or wall portion 31 of the front section 29 is formed with a plurality of key hole openings 99, corresponding in number to the holes 98. In positioning a separating member 93 its reduced end 94 is initially placed within a hole 98, after which the head end 96 thereof is: inserted through a corresponding key hole opening 99 so that the neck 97 is at the opening 99. The separator member 93 is then turned to position the head portion 96 transversely of the key hole opening 9f. Since a separating member is spaced vertically above the article supporting units 46 they function efficiently to maintain the articles to be displayed in rows extended longitudinally of the tray unit 22.

, In this connection, it is to be noted that when a tray unit 22 is filled with articles, that the bail 40 functions as a guard to keep the articles from falling ofi a tray unit over the front end thereof. It is to be also noted that the construction of the front section 29 eliminates any rough edges at the front end of a tray unit 22 so as to eliminate any chance of possible injury to a person in the handling of a tray unit 22, or in the handling of articles in the tray unit.

In one embodiment of the invention a tray unit 22 is about twenty-seven inches square and includes eleven supporting units 46. In this embodiment the frame member 48 of an article supporting unit 46 is one and one-eighth inches wide, having legs 49 and 50 about one-half inch long, and with the openings 54 in the base 51 being nine-sixteenths of an inch wide. The rollers 47 are of a plastic material and have a diameter of fiveeighths of an inch, and when assembled in a frame member 48, the centers of adjacent rollers are spaced a distance apart equal to one and one-half inches. The openings 57 in the legs 49 and 50 are located such that with the roller shafts 56 positioned therein the rollers 47 project an eighth of an inch from the base 51 of the frame member 48. This position of the shafts 56 is obtained with a dimension of nine-sixteenths inch for the transverse width of an opening 54 in the base 51.

By virtue of the projection of a roller 47 above the base 51 one-eighth of an inch, as indicated by the letter X in Fig. 11, and the center distance between adjacent rollers being one and one-half inches, as indicated by the letter Y in Fig. 11, the bottom surface 100 of a soft goods article 101, such as a cellophane wrapped bread or cake, is supported on both the rollers 47 and on the flat portions 102 of the base 51 between adjacent rollers 47. In its travel over the article supporting units 46, and because of the yielding bottom surface 100, of the article 1101, the surface 100 tends to follow over the rollers 47 and surfaces 102, with what might be called a caterpillar action, namely yielding or giving to the contour of its path of travel. Thus the drag of the article 101 on the surfaces 00 and its free moving action over the rollers 47 are noncontinuous and counteracting. Stated otherwise, the drag on the surfaces 100 functions as a brake to retard the free roll of the articles on the rollers 47, but with this braking action being less than the action of gravity for moving the article 101.

Additionally, the bottom surface 100 of the article 101 is of a catenary contour at the surfaces 102 so as to give a sled runner rather than a stone boat traveling action on the surfaces 102, whereby a bunching or rearward movement of the cellophane wrapping, relative to the forward movement of the article 101, is substantially eliminated. It is to be noted that the surface 100 of the article 101, at a position above a roller 47, is of a reversed catenary form to again reduce any tendency of the cellophane wrapping to bunch at a roller. This counteracting, complementary action of the rollers 47 and surfaces 102 is highly important in maintaining a travel downwardly of soft goods in a tray unit, by the action of gravity, at a rate to successively feed articles to the front of a trayunit 22, but without any damaging impact of the goods with the front section 29.

' In the use of hard goods in a tray unit 22, it will be apparent that since the under surfaces of these hard goods are substantially rigid, they will be supported entirely on the rollers 47 and free of the surfaces 102. It will also be apparent that by virtue of being hard goods, the inclination of the tracks 23 may be maintained at the same inclination used for soft goods, since there would be little or no danger of the hard goods being damaged on impact to a stop position with the front section 29.

Although this invention has been described with respect to a preferred embodiment thereof, it is to be understood that his not to be so limited since changes can be made therein which are within the full intended scope of this invention as defined by the appended claims.

I claim:

1. In a tray for a delivery and display stand, an article supporting roller unit comprising a channel shaped frame member having a base section and leg sections, said base section having a plurality of longitudinally spaced roller receiving openings, a plurality of roller and shaft assem blies corresponding to said openings, with the shafts of said assemblies being of a length substantially equal to the transverse dimension of said frame member, said leg sections having pairs of transversely opposite openings formed with continuous side walls and corresponding in number to the openings in said base section for axially receiving therein the ends of the shaft of a corresponding roller and shaft assembly, and shaft confining means on said leg sections arranged in an overlying relation with an opening in a leg section to maintain a corresponding shaft within the transverse confines of said frame member, with the rollers of said roller and shaft assemblies being of a diameter to project outwardly from said base section.

2. In a tray for a delivery and display stand for cellophane wrapped articles, an article supporting roller unit comprising a channel shaped frame member having a base section and leg sections, said base section having a plurality of longitudinally spaced roller receiving openings therein, a plurality of roller and shaft assemblies corresponding to said base section openings, with the shafts of said rollers being supported in said leg sections at positions providing for the projection of the rollers from said base section, with the distance between centers of adjacent roller and shaft assemblies being substantially equal to twelve times the distance a roller is projected outwardly of a corresponding base opening, to provide for the movement by gravity of cellophane wrapped articles on said rollers and base section free of any bunching of the cellophane wrapping with the projected portion of a roller and said base section.

3. In a tray for a delivery and display stand, an article supporting roller unit comprising a channel shaped frame member having a base section and leg sections, said base section having a plurality of longitudinally spaced roller receiving openings and said leg sections being bendable relative to said base section, a plurality of roller and shaft assemblies corresponding to said openings, with the shafts of said assemblies being of a length substantially equal to the transverse dimension of said base section, said leg sections having pairs of transversely opposite openings therein cor-responding in number to the openings in said base section for axially receiving therein the ends of the shaft of a corresponding roller and shaft assembly on bendable movement of said leg sections from positions diverged relative to said base section to positions extended normal to said base section, and shaft confining means on said leg sections arranged in an overlying relation with an opening in a leg section to maintain a corresponding shaft within the transverse confines of said base section, with the is rollers of said roller and shaft assemblies being of a diameter to project outwardly from said base section.

References Cited in the file of this patent UNITED STATES PATENTS 1,381,191 Higson June 14, 1921 1,667,913 Weston May 1, 1928 1,840,638 Scribner Jan. 12, 1932 10 Bales Apr. 19, 1932 Boden Nov. 1, 1932 Keil May 2, 1933 Sebastian Dec. 28, 1948 Bentley Nov. 2, 1954 01k et a1 Mar. 18, 1958 FOREIGN PATENTS Great Britain May 29, 1957 

